The present invention relates to the production of liquid fuels and, more specifically, to reducing, upon combustion of high boiling petroleum fuels and additives, the detrimental effect of sulphur, sodium and vanadium constituents on structural components of equipment utilizing the fuel.
The present invention appears to be most useful in the fuel industry as well as in energetics and other applications including combustion of a fuel, mainly in boiler units, gas turbines, vaporgas plants, heating furnaces and the like.
Combustion of a petroleum fuel containing sulphur, sodium and vanadium compounds results in corrosion, slagging and clogging, with ash deposits on equipment utilizing the fuel.
An effective means adapted for preventing the detrimental effects resides in the use of mineral additives introduced into the flue gases resulting from combustion of a petroleum fuel. Interaction of such an additive with the fuel ash results in an increase of the ash melting point and loss, thereby, of the ability to form dense deposits on equipment utilizing the fuel as well as in deactivation of corrosion-active components of the combustion products and a sharp decrease in the dew point of the flue gases.
Most technologically simple and readily available, especially in heavy-duty devices, is the method of introducing said additives along with the fuel in the form of a composition prepared in advance or during the fuel supply for combustion or during the process of fuel combustion.
Known in the art are fuel compositions containing highboiling petroleum fuels and an additive based on finely dispersed compounds of elements pertaining to the group of Si, Al and Mg (cf. German (Democratic Republic) Pat. No. 52,761 Cl. 24 B 1/01, 23 d of May 16, 1964).
These prior art fuel compositions and processes for producing same feature a disadvantage residing in that the additive incorporates compounds of not all the elements which may be used for the above-mentioned purposes; another disadvantage resides in the necessity of preliminary fine grinding of said solid components of the additive. This is accompanied by high energy costs, utilization of ineffective and expensive equipment, complicated technology of the composition preparation and low reactivity of the additive components. Furthermore, such compositions feature limited stability and can cause erosion of the fuel-supply system members.
Said disadvantages can be partially overcome by a widened range of the elements incorporated into the additive, such as compounds of elements pertaining to the group of Mn, Fe and Ca, as well as due to preliminary suspending thereof in an intermediate liquid as disclosed, for example, in U.S. Pat. No. 3,332,755 of July 25, 1967, Cl. 44-4.
According to said U.S. Patent, the fuel composition contains a high-boiling fuel oil and an additive incorporating compounds of the elements selected from the group of Si and/or Ca and/or Mg, and/or Al, and/or Fe, and/or Mn.
To prepare the additive, compounds of said active elements are mixed with a liquid incorporating surface-active agents, light oils of mainly naphthenic origin, or volatile oil distillates or cresol, or liquid amines as well as glycol ether, a gelatinizing agent or a pigment stabilizer, a hydrophilic colloid and water.
Since compounds of the active elements should be incorporated into the additive in the form of a fine dust, they are subjected to thorough grinding either prior to intermixing with the liquid or during this operation.
Said fuel composition and process for producing same have the following disadvantages.
A great number of relatively expensive raw materials are required for the preparation of said additive.
In the additive preparation active components are finely ground which necessitates using expensive, ineffective, energy consuming equipment.
Stability of the additive and fuel composition is achieved by incorporating therein an expensive, multicomponent intermediate liquid.
At the same time, increasing power demand and limited sources of high-quality fuels stimulate the use of low-grade solid fuels. Since combustion of low-grade fuels is less efficient, said fuels are subjected to preliminary heat-treatment to obtain liquid and gaseous fuels.
In so doing, however, a substantial portion of the liquid fuel thus obtained has a high ash content.
A mixture of resin vapors and gases resulting from the thermal decomposition of the solid fuel (vapor-gas mixture) entrains therewith a fine ash of the thus-processed fuel. At further stages, upon condensation, said ash is deposited with the resin (mainly with its heavier fractions).
Such high-ash content resins do not find wide application.
To reduce the ash content in commercial products, the vapor-gas mixture and condensed resins are subjected to purification. As a consequence, capital investment and production costs of the industrial plants increase substantially. A portion of the resin is lost with the ash removed therefrom and environmental pollution occurs.